Curved conveyor section

ABSTRACT

A curved conveyor section comprises a generally flat substantially horizontally disposed curved belt-supporting bed having first and second opposite ends and first and second direction reversing members disposed at the first and second opposite ends, respectively. A continuous loop curved conveyor belt has arcuate inner and outer edges with a common substantially vertical centre axis and is mounted on the belt-supporting bed in looped relation around the direction reversing members so as to have an article carrying portion disposed above the belt-supporting bed and a return portion disposed below the belt-supporting bed, thus defining a looped path for the conveyor belt and presenting a substantially horizontal article carrying top surface. A motor driven continuous loop drive chain or belt is oriented in a substantially horizontal plane and has a plurality of driving members disposed along its looped length. A plurality of driven receptors are securely mounted on the curved conveyor belt along its looped path. The driving members drivably engage a consecutive subset of the plurality of co-operating receptors, which consecutive subset is disposed at one of the article carrying portion and the return portion of the curved conveyor belt, so as to thereby impart a driving force to the co-operating receptors, thus causing selective movement of the curved conveyor belt along its looped path.

CROSS-REFERENCE

This application is a Continuation-In-Part (CIP) application ofcopending U.S. patent application Ser. No. 09/005,798 filed Jan. 12,1998.

FIELD OF THE INVENTION

This invention relates to curved conveyor sections and more particularlyto such curved conveyor sections driven by a drive chain or a drivebelt, especially those having a conveyor belt of a small radius.

BACKGROUND OF THE INVENTION

In manufacturing processes, it is common to move goods along by means ofconveyor systems having straight and curved sections. In many instances,it is desirable that the curved sections be of a small radius, such asto turn at almost a right angle in a confined space. Such curvedconveyor sections typically have a continuous loop conveyor belts or mayhave an articulated linked conveyor belt.

Typically, such curved conveyor belts are driven through the use of alinked drive chain, a linkless drive chain, or a drive belt, each ofwhich has a looped length and is typically driven by an electric motor.The most common way to drive a curved conveyor belt is through the useof a linked drive chain. For the sake of simplicity and clarity, only alinked drive chain will be referred to in this background section. Thedrive chain is in the form of a continuous loop, as is the conveyorbelt, and is disposed at the outer edge of the conveyor belt or alongthe middle of the conveyor belt and directly drives the conveyor belt.

In order to facilitate proper meshing of the drive chain and conveyorbelt, the drive chain must follow the path of the conveyor belt so as tokeep the drive chain at the same speed as the conveyor at all pointsalong the conveyor. Accordingly, the loop of the drive chain isessentially oriented similarly to the loop of the conveyor belt. Inother words, since the conveyor belt is oriented substantiallyhorizontally, the rollers at the ends of the conveyor belt are alsooriented substantially horizontally. In order for the drive chain tofollow the path of the conveyor belt, the axes of the links of the drivechain and the end roller's drive sprockets, which are engaged by thedrive chain, must both be oriented substantially horizontally. In thismanner, the drive chain can articulate vertically around the drivesprockets.

However, in order for a drive chain to follow the same curved path as acurved conveyor belt, it must also bend horizontally along its length,transversely to its usual direction of articulation between adjacentlinks. Conventional chains cannot bend significantly in a directiontransverse to their normal direction of articulation between adjacentlinks, simply due to their construction. The minimum radius that aconventional chain can bend to in such a transverse direction is perhapsabout ten feet, which is far too large a radius to be used in manycurved conveyors. Further, a conventional drive chain is severelystressed by such transverse bending. Special flexible drive chains thatcan bend transversely to their normal direction of articulation may beused, but they are more expensive than conventional chains and stillhave a limited radius of curvature of perhaps four to five feet, whichis larger than is often required as some conveyor bends must be quitesharp, perhaps with an outside radius of about two to three feet.

Another important consideration, irrespective of what type of drivechain is used, is that the drive sprocket on the rollers of the conveyorbelt must have the same pitch diameter as the diameter of the rollers onthe conveyor belt in order to provide for speed matching of the drivechain and conveyor belt. Such drive sprockets typically have a minimumpitch diameter of about three inches, more or less, as dictated by thedrive chain. Accordingly, the minimum diameter of the end roller of acurved conveyor belt is also about three inches, more or less. An endroller having a three inch diameter would cause a significant cleft atthe end of the curved conveyor, where the curved conveyor meets anotherconveyor. It is highly desirable to minimize such clefts in order tofacilitate the smooth transfer of articles, especially readilydamageable articles, from the curved conveyor to the next conveyor. Itis therefore preferable to have the end rollers of a curved conveyor assmall a diameter as possible, perhaps about one-half inch, or even less,which cannot be accomplished by presently known curved conveyors drivenby drive chains unless an auxiliary end roller is also used.

Another manner of driving a curved conveyor belt, specifically acontinuous and unbroken type curved conveyor belt, which overcomes someof the problems encountered with a drive chain arrangement, is to driveone or both of the two end rollers that the conveyor belt is loopedaround, typically by means of an electric motor. This manner of drivinga curved conveyor belt also has significant disadvantages associatedwith it. The conveyor belt must be in tension in order to permit thedriving force from the end roller or end rollers to be frictionallytransmitted to the curved conveyor belt. In order to have the curvedconveyor belt uniformly in tension and the curved conveyor belt musttherefore be manufactured to very close tolerances, which is difficultand expensive, and therefore is undesirable. Moreover, such curvedconveyor belts stretch and therefore require frequent adjustment orreplacement. Further, it is difficult to transport heavy loads usingthis type of drive mechanism as it requires frictional engagement of theend roller or end rollers with the curved conveyor belt. Also, wherearticles such as food products are being conveyed, oils tend to becomedeposited on the conveyor belt, thus potentially causing reducedfriction between the drive roller or drive rollers and the conveyorbelt.

Another method of driving a curved conveyor belt, specifically acontinuous and unbroken type curved conveyor belt, and which alsoovercomes some of the problems encountered with a drive chainarrangement, is to have a portion of the curved conveyor belt pinchedbetween an external auxiliary drive roller and an opposed idler wheelthat is spring biased against the drive wheel. This type of drivemechanism does not work well because the drive belt is driven at onlyone point along the belt. Again, where articles such as food productsare being conveyed, oils tend to become deposited on the conveyor belt,thus potentially causing reduced friction between the external auxiliarydrive roller and the conveyor belt.

It can therefore be seen that not using a drive chain arrangement todrive a curved conveyor belt is often unacceptable.

DESCRIPTION OF THE PRIOR ART

The closest known prior art to the present invention can be found inU.S. Pat. No. 4,846,338, issued Jul. 11, 1989, to WIDMER, whichdiscloses a curved conveyor element comprising inner and outer curvedframe members having first and second ends. A row of cylindrical rollersis disposed at each end of the conveyor. An endless conveyor belt islooped around the two rows of rollers and has an inner side edge and anouter side edge. The conveyor belt rests on a planar contact surfacethat is part of a ring member. Two guide rails are also fastened to thering member, with an annular channel disposed in the outside surface ofeach guide rail. A continuous loop drive chain with the axes of itslinks oriented substantially horizontally is disposed in these twochannels. The conveyor belt is interconnected to the chain by means ofan elastic dog member and suitable other fastening elements. The drivechain must curve transversely to its designed direction of articulation,which is undesirable, and often unacceptable, for reasons as discussedabove. Further, in order to minimize the radius of the end roller, anauxiliary cylindrical end roller must be used, which is alsoundesirable.

Another prior art patent that discloses a curved conveyor is U.S. Pat.No. 3,912,072, issued Oct. 14, 1975 to KORNYLAK, which discloses aradius chain conveyor having a drive chain with the axes of its linksoriented substantially horizontally. As specifically discussed in thedetailed description, ". . . a straight line portion of the chain may betransversely bent, as shown in FIG. 1, so that it will have a radius of,for example, nine feet", which is a completely unacceptable radius ofcurvature for most curved conveyors.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there isprovided a curved conveyor section comprising a generally flatsubstantially horizontally disposed curved belt-supporting bed havingfirst and second opposite ends and first and second direction reversingmembers disposed at the first and second opposite ends, respectively. Acontinuous loop curved conveyor belt of thickness "t_(b) " has arcuateinner and outer edges with a common substantially vertical centre axisand is mounted on the belt-supporting bed in looped relation around thedirection reversing members so as to have an article carrying portiondisposed above the belt-supporting bed and a return portion disposedbelow the belt-supporting bed, thus defining a looped path for theconveyor belt and presenting a substantially horizontal article carryingtop surface. A continuous loop drive means is oriented in asubstantially horizontal plane and has a plurality of driving membersdisposed along its looped length. A motor means drivably engages thecontinuous loop drive means. A plurality of driven receptors aresecurely mounted on the curved conveyor belt along its looped path. Thedriving members drivably engage a consecutive subset of the plurality ofco-operating receptors, which consecutive subset is disposed at one ofthe article carrying portion and the return portion of the curvedconveyor belt, so as to thereby impart a driving force to theco-operating receptors, thus causing selective movement of thecontinuous loop curved conveyor belt along its looped path.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features which are believed to be characteristic of the curvedconveyor section present invention, as to its structure, organization,use and method of operation, together with further objectives andadvantages thereof, will be better understood from the followingdrawings in which a presently preferred embodiment of the invention willnow be illustrated by way of example. It is expressly understood,however, that the drawings are for the purpose of illustration anddescription only and are not intended as a definition of the limits ofthe invention. Embodiments of this invention will now be described byway of example in association with the accompanying drawings in which:

FIG. 1 is a top plan view of a first preferred embodiment of the curvedconveyor section according to the present invention in use conveyingarticles from one straight conveyor to another straight conveyor;

FIG. 2 is a top plan view of the curved conveyor section of FIG. 1 withparts removed or shown in ghost outline for the sake of clarity;

FIG. 3 is a sectional side elevational view of the curved conveyorsection of FIG. 1, taken along section line 3--3 of FIG. 2;

FIG. 4 is an end elevational view of the curved conveyor section of FIG.1;

FIG. 5 is an enlarged end elevational view similar to FIG. 4, butshowing a lesser portion of the curved conveyor section;

FIG. 6 is a top plan view of a tooth assembly used in the curvedconveyor section of the first embodiment of the present invention;

FIG. 7 is an end view of the tooth assembly of FIG. 6;

FIG. 8 is an enlarged top view of the tooth assembly of FIG. 6, showingdeformation of the elastomeric element therein;

FIG. 9 is a top plan view of an alternative embodiment curved conveyorsection of the present invention, with parts cut away for the sake ofclarity;

FIGS. 10, 11, and 12 are simplified top plan views of alternativeembodiment curved conveyor sections of the present invention;

FIG. 13 is a top plan view of a second preferred embodiment curvedconveyor section, with parts removed or shown in ghost outline for thesake of clarity;

FIG. 14 is a sectional side elevational view of the curved conveyorsection of FIG. 13, taken along section line 14--14 of FIG. 13;

FIG. 15 is a top elevational view of a portion of the curved conveyorsection of FIG. 13, with parts removed for the sake of clarity;

FIG. 16 is a slightly enlarged top plan view of a portion of the curvedconveyor section of FIG. 13, with parts removed for the sake of clarity;

FIG. 17 is an end elevational view of the curved conveyor section ofFIG. 13, taken along section line 17--17 of FIG. 16;

FIG. 18 is an enlarged top plan view of one of the teeth to be securedto the conveyor belt of the curved conveyor section of FIG. 13;

FIG. 19 is a side elevational view of the tooth of FIG. 18; and

FIG. 20 is an enlarged top plan view of a further alternative embodimentcurved conveyor section of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to FIGS. 1 through 8, which show a firstpreferred embodiment of the curved conveyor section 20 of the presentinvention, to FIGS. 9, 10, and 11, which show alternative embodiments ofthe curved conveyor section of the present invention, to FIGS. 13through 19, which show a second preferred embodiment of the curvedconveyor section of the present invention, and to FIG. 20, which shows afurther alternative embodiment of the curved conveyor section of thepresent invention.

Referring first to FIG. 1, the curved conveyor section 20 is shown inuse, transporting articles 22, from a first straight conveyor 24 to asecond straight conveyor 26, as indicated by arrows 'B". The articlesmay be food, such as muffins or the like, or may be one of many othertype of manufactured articles. It can be seen in FIGS. 1 and 2 that theoverall direction of travel of the articles 22 is changed by 90° in asmall space by the preferred embodiment curved conveyor section 20. Thedegree of curvature of the curved conveyor section of the presentinvention is not limited to 90°, and may be, for instance, 30°, 45°,60°, or virtually any other desired angle. Typically, the maximum degreeof curvature necessary would be 180°. Also, curved conveyor sections maybe abutted one to another to obtain desired degrees of curvature.

Reference will now be made to FIGS. 2 through 5, which show on anoverall basis the working components of the curved conveyor section 20.The curved conveyor section 20 comprises a generally flat substantiallyhorizontally disposed curved belt-supporting bed 30 having first andsecond opposite ends 31 and 32, respectively, and inner and outer edges33 and 34, respectively. A first direction reversing member 35 isdisposed at the first end 31 and similarly a second direction reversingmember 36 is disposed at the second opposite end. Optional supportrollers 38 are included to support the weight of heavy articles beingconveyed by the curved conveyor section 20. The curved conveyor section20 further comprises a continuous loop curved conveyor belt 40, which inthe preferred embodiment is continuous and unbroken, but may also be ofthe segmented and articulated type, if desired. The continuous loopcurved conveyor belt 40 is shown in FIG. 1 in solid lining and hiddenlining as necessary, in FIGS. 3, 4, and 5 in solid lining, and in FIG. 2in ghost outline for the sake of clarity.

The curved conveyor belt 40 has an arcuate inner edge 42 and an arcuateouter edge 44. The inner and outer edges 42, 44 have substantiallyvertical concentric centre axes "A" and are of substantially constantradius about the respective centre axis "A". The continuous loop curvedconveyor belt 40 is mounted on the belt-supporting bed 30 in loopedrelation around the elongate roller members 35, 36 so as to have anarticle carrying portion 46 disposed above the belt-supporting bed 30and moving in a direction as indicated by arrow "F", and a returnportion 48 disposed below the belt-supporting bed 30 and moving in adirection as indicated by arrow "G", as can be best seen in FIG. 3. Inthis manner, a looped path for the conveyor belt 40 is defined and theconveyor belt 40 presents a substantially horizontal article carryingtop surface 46t and has an opposite undersurface 46u.

In the first preferred embodiment, each of the direction reversingmembers 35, 36 comprises a segmented elongate roller member havingsegments 35a through 35e and 36a through 36e, respectively, freelyrotatably mounted on the belt-supporting bed 30 by means of an axlemember 37 so as to be disposed substantially across the width of theconveyor belt 40. As can be readily appreciated, with the use of acurved conveyor belt 40, the linear speed at any point thereon will bedirectly proportional to the radius of that point from the axis "A". Inother words, the linear speed of the curved conveyor belt 40 is notconstant across its width. In order to accommodate such a continuum ofspeeds across the curved conveyor belt 40, the elongate roller members35,36 are correspondingly tapered with their smaller diameter disposedtoward the inner edge 33 of the curved belt-supporting bed 30 and theirsmaller diameter disposed toward the outer edge 34 of the curvedbelt-supporting bed 30 so as to conform with the increasing radius ofthe continuous loop curved conveyor belt 40 from its inner edge 32 toits outer edge 44. Accordingly, the speed of the perimeter of thetapered elongate roller members 35,36 matches the speed of the curvedconveyor belt 40, thus precluding, or at least minimizing, sliding ofthe curved conveyor belt 40 on the tapered elongate roller members35,36. Also, segmenting of the tapered elongate roller members 35,36further precludes, or at least minimizes, sliding of the curved conveyorbelt 40 on the tapered elongate roller members 35,36; however,segmenting of the tapered elongate roller members 35,36 is notnecessary. It is also possible to use at each end of the curved conveyorbelt 40 elongate roller members having a constant diameter, bothsegmented and non-segmented, as will be discussed subsequently withreference to FIG. 9.

In the first preferred embodiment, a guide rail 50 is mounted on thebelt-supporting bed 30 typically by means of threaded fasteners (notshown) and is disposed below the belt-supporting bed 30 in underlyingrelation thereto. The guide rail 50 extends substantially along thelength of the belt-supporting bed 30, as can be best seen in FIG. 2, andhas a convex arcuate tracking surface 52 with a centre axis "A" that issubstantially coaxial with the centre axes "A" of the inner edge 42 andouter edge 44 of the conveyor belt 40. The convex arcuate trackingsurface 52 on the guide rail 50 has a substantially constant radiusabout its centre axis "A".

A plurality of driven receptors comprising teeth 60 are securely mountedon the curved conveyor belt 40, as will be discussed in greater detailsubsequently, along its looped path, in radially outwardly projectingrelation from the common substantially vertical centre axis "A", as canbe best seen in FIG. 3. The teeth 60 are mounted on the curved conveyorbelt 40 for driven engagement with the continuous loop drive means 70operatively mounted on the curved conveyor section 20 so as to beoriented in a substantially horizontal plane, and in the preferredembodiment so as to be substantially coplanar with the article carryingportion 46 of the curved conveyor belt 40. The continuous loop drivemeans 70 has a plurality of driving members 72 disposed along its entirelooped length, with the driving members 72 being regularly spaced apartone from the next by a pitch "P", as can be best seen in FIG. 3. Thedriving members 72 comprise co-operating void portions 73 for receivingthe teeth 60 of the curved conveyor belt 40, and thereby drivably engagea consecutive subset of the plurality of co-operating receptors, namelythe teeth 60 at either the article carrying portion 46 or the returnportion 48 of the continuous looped curved conveyor belt 40 depending onthe vertical placement of the continuous loop drive means 70. The teeth60 along the remainder of the continuous looped curved conveyor belt 40are not engaged until they reach the portion of the path where theybecome part of the engaged consecutive subset of teeth 60. The drivingmembers 72 thereby impart a driving force to the co-operating teeth 60,thus causing selective movement of the continuous loop curved conveyorbelt 40 along its looped path.

In the first preferred embodiment, the drive means 70 comprises acontinuous loop drive chain 70 having a plurality of links 72 pivotallyconnected seriatim one to another by means of pins 74, with voidportions 73 disposed between the links 72. The continuous loop drivechain 70 is oriented for pivotal movement of each link 72 with respectto adjacent links 72 about substantially vertically oriented axes "C",which axes "C" are generally centrally disposed through the pins 74. Thedrive chain 70 is operatively mounted on the curved conveyor section 20around a drive sprocket 76 disposed adjacent the first end 31 of thecurved belt-supporting bed 30 and a cooperating free-wheeling sprocket78 disposed adjacent the second end 32 of the belt-supporting bed 30.The drive sprocket 76 and free-wheeling sprocket 78 typically each havethe same pitch diameter "D_(P) " as the other, but not necessarily so.One advantage of the present invention is that the pitch diameter "D_(P)" of the sprockets 76,78 does not need to be the same as the maximumdiameter "D_(M) " of the elongate roller members 35,36. The returnportion of the continuous loop drive chain 70 is fed around idlersprocket 71 to keep it separated from the portion of the drive chain 70that is engaging some of the teeth 60.

In the first preferred embodiment, as illustrated, the continuous loopdrive chain 70 is positioned to drivably engage a consecutive subset ofthe plurality of teeth 60 disposed at the article carrying portion 46 ofthe curved conveyor belt 40. Further, the continuous loop drive chain 70is substantially co-planar with the article carrying portion 46 of thecurved conveyor belt 40 so as to permit proper engagement of theplurality of teeth 60 with the links 72 of the drive chain 70.Alternatively, the continuous loop drive chain 70 may be disposed at thereturn portion 48 of the conveyor belt, in which case would also besubstantially co-planar with the return portion 48. In any event, theplurality of teeth 60 are mounted on the curved conveyor belt 40 so asto be oriented and properly aligned with the openings of the links 72 ofthe continuous loop drive chain 70.

The plurality of teeth 60 are securely mounted on the curved conveyorbelt 40 by means of mounting assemblies 62, as can be best seen in FIGS.6 through 8. Each mounting assembly 62 includes a main body member 64secured to the curved conveyor belt 40 by means of rivets (not shown).In the preferred embodiment, the mounting assemblies 62 are secured tothe curved conveyor belt 40 at the arcuate outer edge 44 thereof, butmay also be secured to the curved conveyor belt 40 between the arcuateinner edge 42 and the arcuate outer edge 44. In this event, the mountingassembly 62 are disposed at the undersurface 46u of the article carryingportion 46 of the curved conveyor belt 40 so as to not interfere witharticles 22 being conveyed by the curved conveyor belt 40.

Each of the plurality of teeth 60 includes a mounting base 59 and ismounted on the respective mounting assembly 62 by means of a pin member63 and a pin member 69 extending through co-operating apertures 63a, 69ain the mounting base 59. A substantially cylindrical elastomeric member68 is operatively mounted in surrounding relation around the pin member69, between the pin member 69 and the mounting base 59, whichelastomeric member 68 causes the respective tooth 60 to be biased to aneutral centre position.

Two roller bearing members 66 are each operatively mounted on the mainbody member 64 of the mounting assembly 62 by means of a respective pinmember 67, for rolling contact with the convex arcuate tracking surface52 on the guide rail 50. The teeth 60, or more specifically the rollerbearing members 66, are in abutting relation against the trackingsurface 52 of the guide rail 50, as can be best seen in FIGS. 6 and 7.In this manner, the teeth 60 are laterally supported during movement ofthe curved conveyor belt 40 along its looped path, and thus the teeth 60remain engaged in the drive chain 70. Accordingly, the portion of thecontinuous loop drive chain 70 that is in engagement with the teeth 60is also laterally supported by the tracking surface 52. The teeth 60 atthe return portion 48 of the continuous loop curved conveyor belt 40 aresupported on a support rail 39 by means of two roller bearing members 61mounted to the main body member 64 by means of respective pin members65.

It can be seen that in order for the teeth 60 to properly engage thedrive chain 60, the plurality of teeth must be spaced apart one from thenext by a distance that is an integer multiple of the pitch of the drivechain. The teeth 60 may be spaced apart so as to engage the spacebetween each and every adjacent link 72, or instead, as in the preferredembodiment, may engage the space between every "Nth" adjacent link 72,where "N" is a positive integer greater than one. In that case, theplurality of teeth are spaced apart one from the next by a distance thatis an integer multiple of the pitch of the drive chain 70, with theinteger multiple being greater than one. Preferably, the integermultiple is from two to ten. Also, the spacing between the adjacentteeth 60 does not need to be constant and can vary, thus precluding theneed for having a specific number of links in the drive chain 70.

In use, as the teeth 60 are about to enter the spaces between adjacentlinks 72 of the drive chain 70, as can be best seen in FIG. 8, the teeth60 might or might not be precisely aligned with the respective space. Inorder to assist the teeth 60 to readily enter the spaces betweenadjacent links 72, the elastomeric member 68 permits a minor amount ofrotation of the mounting base 59 about the pin member 63, as indicatedby arrows "H". Such rotation of the mounting base 59 essentiallytranslates to a minor amount of longitudinal displacement of therespective tooth 60, as indicated in dashed outline, in a directionalong the length of the conveyor belt 40, both back and forth, when theteeth 60 are engaging the drive chain 70. Accordingly, if a tooth 60 isnot properly aligned with the corresponding space between the adjacentlinks 72, the elastomeric member 68 permits the tooth 60 to align itselfas the tooth tries to enter the space between adjacent links 72.Alternatively, the elastomeric member 68 may be replaced by one or moresprings, or the like, in order to cause the tooth 60 to be biased to aneutral centre position. Also, elastomeric member 68 may be replaced bya similarly shaped rigid member made from a material such as suitableplastic or metal, if longitudinal displacement of the tooth 60, asdiscussed above, is not required.

A motor means, preferably an electric motor 80, is securely mounted onthe curved conveyor section 20 so as to rotatably drive the drivesprocket 76, thus drivably engaging the continuous loop drive chain 70,thereby imparting a driving force to the teeth 60, thus causingselective movement of the continuous loop curved conveyor belt 40 alongits looped path, as is shown by arrows "E" in FIG. 3, thus permittingconveying of articles 22 as shown in FIG. 1 by arrows "B".

In the first preferred embodiment, the curved conveyor section 20further comprises a ramp member (not shown) securely mounted on thebelt-supporting bed 30, which receives and positions the plurality ofteeth 60 as they transition from the return portion 48 and approach thearticle carrying portion 46, so that the teeth 60 can properly engagethe links 72 of the continuous loop drive chain 70.

It can be seen that the axes of rotation of the sprockets 76,78 aresubstantially vertically oriented, as are the axes "C" of the links 72of the continuous loop drive chain 70. In this manner, the drive chainmay readily follow the curved path of the conveyor, specifically alongthe outer edge 44 of the curved conveyor belt 40, and not experience anytransverse bending of the links 72 of the drive chain 70, which isimpossible with the chain driven conveyors in the prior art.

In an alternative embodiment of the present invention, as illustrated inFIG. 9, each of the elongate roller members 35',36' is of asubstantially constant diameter along its length. If such substantiallyconstant diameter elongate roller members 35',36' are used, it isnecessary for them to be longitudinally segmented, such as in fiveaxially aligned segments 35a' through 35e' and 36a' through 36e'. Use ofsuch segmented cylindrical elongate roller members 35a' through 36e' atleast minimizes or lessens sliding of the curved conveyor belt 40 on thecylindrical elongate roller members 35',36'.

In another alternative embodiment of the present invention, asillustrated in FIG. 10, the continuous loop drive means comprises adrive belt 90 having drive members 92 and cooperating void portions 94for receiving teeth 60 therein.

In yet another alternative embodiment of the present invention, as shownin FIG. 11, the continuous loop drive means comprises a drive belt 100.The driving members on the drive belt 100 comprises teeth 102 disposedalong the looped length of the drive belt 100. Each the driven receptors104 on the continuous loop curved conveyor belt 106 defines acooperating void portion 108 for receiving the teeth 102 in drivingrelation therein.

In another similar alternative embodiment of the present invention, asshown in FIG. 12, the continuous loop drive means comprises a linklesschain 110 having a plurality of protrusions 112 disposed along thelooped length of the linkless chain 110. Each the driven receptors 114on the continuous loop curved conveyor belt 116 defines a co-operatingvoid portion 118 for receiving the protrusions 112 in driving relationtherein.

In yet another alternative embodiment of the present invention (notshown), the two roller bearing members 66 are replaced by a low-frictionplastic element that slides along the convex arcuate tracking surface52, or may also be replaced by other types of low-friction plasticelements such as hangers that would engage a co-operating track.

Reference will now be made to FIGS. 13 through 19, which show a secondpreferred embodiment of the curved conveyor section according to thepresent invention. The second preferred embodiment curved conveyorsection is indicated by the general reference numeral 220, and hasspecific differences as compared to the first preferred embodimentcurved conveyor section 20, as will become apparent from the followingdescription.

The curved conveyor section 220 comprises a generally flat substantiallyhorizontally disposed curved belt-supporting bed 230 having first andsecond opposite ends 231 and 232, respectively, and inner and outeredges 233 and 234, respectively. A first direction reversing member 235is disposed at the first end 231 an similarly a second directionreversing member 236 is disposed at the second opposite end. The curvedconveyor section 220 further comprises a continuous loop curved conveyorbelt 240, which in the preferred embodiment is continuous and unbroken,but may also be of the segmented and articulated type, if desired.

The curved conveyor belt 240 of thickness "t_(b) " has an arcuate inneredge 242 and an arcuate outer edge 244. The inner and outer edges 242,244 have substantially vertical concentric centre axes "I" and are eachof substantially constant radius about the respective centre axis "I".The continuous loop curved conveyor belt 240 is mounted on thebelt-supporting bed 230 in looped relation around the elongate rollermembers 235, 236 so as to have an article carrying portion 246 disposedabove the belt-supporting bed 230 and moving in a direction as indicatedby arrow "J", and a return portion 248 disposed below thebelt-supporting bed 230 and moving in a direction as indication by arrow"K", as can be best seen in FIG. 14. In this manner, a looped path forthe conveyor belt 240 is defined and the conveyor belt 240 presents asubstantially horizontal article carrying top surface 246t and has anopposite undersurface 246u.

In the second preferred embodiment curved conveyor section 220, each ofthe direction reversing members 235, 236 comprises a segmented elongateroller member having segments 235a through 235e and 236a through 236e,respectively, freely rotatably mounted on the belt-supporting bed 230 bymeans of an axle member 237, so as to be disposed substantially acrossthe width of the conveyor belt 240. As in the first preferredembodiment, with the use of a curved conveyor belt 240, the linear speedat any point thereon will be directly proportional to the radius of thatpoint from the axis "I". In other words, the linear speed of the curvedconveyor belt 240 is not constant across its width. In order toaccommodate such a continuum of speeds across the curved conveyer belt240, the elongate roller members 235, 236 are correspondingly taperedwith their smaller diameter disposed toward the inner edge 233 of thecurved belt-supporting bed 230 and their smaller diameter disposedtoward the outer edge 234 of the curved belt-supporting bed 230 so as toconform with the increasing radius of the continuous loop curvedconveyor belt 240 from its inner edge 232 to its outer edge 244.Accordingly, the axes of the tapered elongate roller members 235, 236intersect the vertical axis "I" of the inner edge 242 and the outer edge244, and the speed of the perimeter of the tapered elongate rollermembers 235, 236 matches the speed of the curved conveyor belt 240, thusprecluding, or at least minimizing, sliding of the curved conveyor belt240 on the tapered elongate roller members 235, 236. Also, segmenting ofthe tapered elongate roller members 235, 236 further precludes, or atleast minimizes, sliding of the curved conveyor belt 240 on the taperedelongate roller members 235, 236; however, segmenting of the taperedelongate roller members 235, 236 is not necessary. It is also possibleto use at each of the curved conveyor belt 240 cylindrical elongateroller members having a constant diameter, both segmented andnon-segmented. In this case, the axes of the cylinder rollers do notpass through the axes "I" of the inner edge 242 and the outer edge 244.

In the second preferred embodiment curved conveyor section 220, a guiderail 250 is mounted on the belt-supporting bed 230 typically by means ofthreaded fasteners (not shown) and is disposed below the belt-supportingbed 230 in underlying relation thereto. The guide rail 250 extendssubstantially along the length of the belt-supporting bed 230, as can bebest seen in FIG. 13, and has a convex arcuate tracking surface 252 witha centre axis "I" that is substantially coaxial with the centre axes "I"of the inner edge 242 and outer edge 244 of the conveyor belt 240. Theconvex arcuate tracking surface 252 on the guide rail 250 has asubstantially constant radius about its centre axis "I".

A plurality of driven receptors comprises a first set of teeth 260, eachtooth 260 having a secured end 260 and a free end 260b. The teeth 260are securely mounted on the curved conveyor belt 240, along its loopedpath, in radially outwardly projecting relation from the commonsubstantially vertical centre axis "I", as can be best seen in FIG. 15.As can be seen in FIGS. 18 and 19, the teeth 260 are substantially flatand have a thickness "t_(t) ", which thickness "t_(t) " is between twoand six times the thickness "t_(b) " of the conveyor belt 240.Preferably, the teeth 260 comprise a top segment 260t, an intermediatesegment 260i, and a bottom segment 260b. The top segment 260t and thebottom segment 260b extend toward the secured end 260a beyond theintermediate segment 260c, thereby forming a gap 268 between the topsegment 260t and the bottom segment 260b at the secured end 260a. Thetop segment 260t, the intermediate segment 260i, and the bottom segment260b are securely joined one to the other in layered relation by rivets262 extending through co-operating apertures 264 in the top segment 260tand the bottom segment 260b. The rivets 262 also secure the teeth 260 tothe conveyors belt 240 along the arcuate outer edge 244, with the gap268 receiving and retaining the arcuate outer edge 244 of the conveyorbelt 240.

The drive means 270 comprises a continuous loop drive chain 270 having aplurality of links 277 pivotally connected seriatim one to another bymeans of pins 274. The continuous loop drive chain 270 is oriented forpivotal movement of each link 277 with respect to adjacent links 277about substantially vertically oriented axes "L", which axes "L" aregenerally centrally disposed through the pins 274. The drive chain 270is operatively mounted on the curved conveyor section 220 around a drivesprocket 276 disposed adjacent the first end 231 of the curvedbelt-supporting bed 230 and a co-operating free-wheeling sprocket 278disposed adjacent the second end 232 of the belt-supporting bed 230. Thedrive sprocket 276 and free-wheeling sprocket 279 typically each havethe same pitch diameter "D_(P) " as the other, but not necessarily so.One advantage of the present invention is that the pitch diameter "D_(P)" of the sprockets 276, 278 does not need to be the same as the maximumdiameter "D_(M) " of the elongate roller members 235, 236. The returnportion of the continuous loop drive chain 270 is fed around idlersprocket 271 to keep it separated from the portion of the drive chain270 that is engaging some of the teeth 260.

The continuous loop drive means 270 has a plurality of driving membersdisposed along its entire looped length, with the driving members beingregularly spaced apart one form the next by a pitch "P", as can be bestseen in FIG. 14. The driving members comprise a second set ofco-operating teeth 272 each having a secured end 272a and a free end272b. The teeth 272 each comprise a base portion 273 secured to a link277 in the drive chain 270. A rounded cap portion 275 made from a lowfriction material is disposed over the end of the base portion 273.Also, as can be best seen in FIGS. 15 and 18, the teeth 260 of the firstset of teeth are rounded at their free ends 260b to readily intermeshwith the teeth 272 of the second set of teeth.

The teeth 260 of the first set of teeth are mounted on the curvedconveyor belt 240 for driven engagement with the continuous loop drivemeans 270 operatively mounted on the curved conveyor section 220 so asto be oriented in a substantially horizontal plane, and in the secondpreferred embodiment so as to be substantially coplanar with the articlecarrying portion 246 of the curved conveyor belt 240. The teeth 272drivably engage a consecutive subset of the plurality of co-operatingreceptors, namely the teeth 260 at either the article carrying portion246 or the return portion 248 of the continuous looped curved conveyorbelt 240 depending on the vertical placement of the continuous loopdrive means 270. The teeth 260 along the remainder of the continuouslooped curved conveyor belt 240 are not engaged until they reach theportion of the path where they become part of the engaged consecutivesubset of teeth 260. The drive members 272 thereby impart a drivingforce to the co-operating teeth 260, thus causing selective movement ofthe continuous loop curved conveyor belt 240 along its looped path.

In the second preferred embodiment, as illustrated, the continuous loopdrive chain 270 drivably engages a consecutive subset of the pluralityof teeth 260 disposed at the article carrying portion 246 of the curvedconveyor belt 240. Further, the continuous loop drive chain 270 issubstantially co-planar with the article carrying portion 246 of thecurved conveyor belt 240 so as to permit proper engagement of theplurality of teeth 260 with the links 277 of the drive chain 270.Alternatively, the continuous loop drive chain 270 may be disposed atthe return portion 248 of the conveyor belt, in which case would also besubstantially co-planar with the return portion 248. In any event, theplurality of teeth 260 are mounted on the curved conveyor belt 240 so asto be oriented and properly aligned with the opening of the links 277 ofthe continuous loop drive chain 270.

As can be best seen in FIG. 17, a roller bearing member 266 isoperatively mounted on a post member 267 disposed in surroundingrelation around one of the rivets, 262, for rolling contact with theconvex arcuate tracking surface 252 on the guide rail 250. The teeth260, or more specifically the roller bearing members 266, are inabutting relation against the tracking surface 252 of the guide rail250. In this manner, the teeth 260 are laterally supported duringmovement of the curved conveyor belt 240 along its looped path, and thusthe teeth 260 remain engaged in the drive chain 270. Accordingly, theportion of the continuous loop drive chain 270 that engages some of theteeth 260 is also laterally supported by the tracking surface 252.Similarly, the teeth 260 at the return portion 248 of the continuousloop curved conveyor belt 240 are laterally supported by a trackingsurface 238 on a support rail 239.

The portion of the continuous loop drive chain 270 that is in engagementwith the teeth 260 at the article carrying portion 246 of the curvedconveyor belt 240 is disposed within a channel 290 in a protectivehousing 291. The teeth 272 are in sliding contact with a supportingsurface 292 defined by the channel 290, in order to keep that portion ofthe drive chain 270 at a desired radius of curvature about the axis "I".The teeth 260 at the article carrying portion 246 of the curved conveyorbelt 240 accordingly enter a slot 294 in the protective housing 291,which slot 294 leads to the channel 290. Similarly, the teeth 260 at thereturn portion 248 of the curved conveyor belt 240 enter a rectangularcross-section slot 296 in a housing 298.

It can be seen that, in order for the teeth 260 to properly engage thedrive chain 260, the plurality of teeth must be spaced apart one fromthe next by a distance that is an integer multiple of the pitch of thedrive chain. The teeth 260 may be spaced apart so as to engage the spacebetween each and every adjacent link 277, or instead, as in thepreferred embodiment, may engage the space between every "Nth" adjacentlink 277, where "N" is a positive integer greater than one. In thatcase, the plurality of teeth are spaced apart one from the next by adistance that is an integer multiple of the pitch of the drive chain270, with the integer multiple being greater than one. Preferably, theinteger multiple is from 2 to 10. Also, the spacing between the adjacentteeth 260 does not need to be constant and can vary, thus precluding theneed for having a specific number of links in the drive chain 270.

A motor means, preferably an electric motor 280, is securely mounted onthe curved conveyor section 220 so as to rotatably drive the drivesprocket 276, thus drivably engaging the continuous loop drive chain270, thereby imparting a driving force to the teeth 260, thus causingselective movement of the continuous loop curved conveyor belt 240 alongits looped path, as is shown by arrow "J" in FIG. 14, thus permittingthe conveying of articles.

In the preferred embodiment, the curved conveyor section 220 furthercomprises a ramp member (not shown) securely mounted on thebelt-supporting bed 30, which receives and positions the plurality ofteeth 260 as they transition from the return portion 248 and approachthe article carrying portion 246, so that the teeth 260 can properlyengage the links 277 of the continuous loop drive chain 270.

It can be seen that the axes of rotation of the sprockets 276, 278 aresubstantially vertically oriented, as are the axes "L" of the links 277of the continuous loop drive chain 270. In this manner, the drive chainmay readily follow the curved path of the conveyor, specifically alongthe outer edge 244 of the curved conveyor belt 240, and not experienceany transverse bending of the links 277 of the drive chain 270, which isimpossible with the chain driven conveyors in the prior art.

In a further alternative embodiment of the present invention, asillustrated in FIG. 20, which alternative embodiment is similar to thesecond preferred embodiment, the teeth 300 of the second set of teetheach comprise a base portion 302 secured to a link 304 in the drivechain 306 and a roller 308 mounted in freely rotatable relation on thebase portion 302. The rollers 308 reduce rolling resistance along theguide rail 310.

Other modifications and alterations may be used in the design andmanufacture of the apparatus of the present invention without departingfrom the spirit and scope of the accompanying claims.

Throughout this specification and the claims which follow, unless thecontext requires otherwise, the word "comprise", and variations such as"comprises" or "comprising", will be understood to imply the inclusionof a stated integer or step or group of integers or steps but not to theexclusion of any other integer or step or group of integers or steps.

Moreover, the word "substantially" when used with an adjective or adverbis intended to enhance the scope of the particular characteristic; e.g.,substantially planar is intended to mean planar, nearly planar and/orexhibiting characteristics associated with a planar element.

What is claimed is:
 1. A curved conveyor section characterized by:agenerally flat substantially horizontally disposed curvedbelt-supporting bed having first and second opposite ends and first andsecond direction reversing members disposed at said first and secondopposite ends, respectively; a continuous loop curved conveyor belt ofthickness "t_(b) " and having arcuate inner and outer edges with acommon substantially vertical centre axis, said continuous loop curvedconveyor belt being mounted on said belt-supporting bed in loopedrelation around said direction reversing members so as to have anarticle carrying portion disposed above said belt supporting bed and areturn portion disposed below said belt-supporting bed, thus defining alooped path for said conveyor belt and presenting a substantiallyhorizontal article carrying top surface; a continuous loop drive meansoriented in substantially horizontal plane and having a plurality ofdriving members disposed along its looped length and regularly spacedapart one from the next by a pitch "P"; motor means drivably engagingsaid continuous loop drive means; and a plurality of driven receptorssecurely mounted on said curved conveyer belt along its looped path;wherein said driven receptors comprise a first set of teeth each havinga secured end and a free end, and said driving members comprise a secondset of co-operating teeth each having a secured end and a free end; andwherein said plurality of driving members drivably engage a consecutivesubset of said plurality of co-operating receptors, which consecutivesubset is disposed at one of said article carrying portion and saidreturn portion of said curved conveyor belt, so as to thereby impart adriving force to said co-operating receptors, thus causing selectivemovement of said continuous loop curved conveyor belt along its loopedpath.
 2. The curved conveyor section of claim 1, wherein said teeth ofsaid first set of teeth are mounted on said conveyor belt in radiallyoutwardly projecting relation from said common substantially verticalcentre axis.
 3. The curved conveyor section of claim 2 wherein saidteeth of said first set of teeth are substantially flat and have athickness "t_(t) ".
 4. The curved conveyor section of claim 3, whereinsaid thickness "t_(t) " of said teeth is between two and six times thethickness of "t_(b) " of said conveyor belt.
 5. The curved conveyorsection of claim 4, wherein said teeth of said first set of teethcomprise a top segment, and intermediate segment, and a bottom segmentsecurely joined one to the other in layered relation.
 6. The curvedconveyor section of claim 5, wherein said top and bottom segments extendtoward said secured end of said tooth beyond said intermediate segment,thereby forming a gap between said top and bottom segments at saidsecured end, which gap receives and retains said arcuate outer edge ofsaid conveyor belt.
 7. The curved conveyor section of claim 6, whereinsaid teeth of said first set of teeth are rounded at said free end. 8.The curved conveyor section of claim 7, wherein said continuous loopdrive means comprises a drive chain having a plurality of linkspivotally connected seriatim one to another and oriented for pivotalmovement of each said link with respect to adjacent links aboutsubstantially vertically oriented axes.
 9. The curved conveyor sectionof claim 1, wherein said teeth of said second set of teeth each comprisea base portion secured to a link in said drive chain and a cap portionmade from a low friction material and disposed over said base portion.10. The curved conveyor section of claim 1, wherein said teeth of saidsecond set of teeth each comprise a base portion secured to a link insaid drive chain and a roller mounted in freely rotatable relation onsaid base portion.
 11. The curved conveyor section of claim 1, furthercomprising a plurality of rollers mounted on said conveyor beltproximate said arcuate outer edge, each for rotation about a respectivesubstantially vertical axis, for rolling contact with said convexarcuate tracking surface on said guide rail.
 12. The curved conveyorsection of claim 1, further comprising a guide rail (50, 250) mounted onsaid belt-supporting bed and extending substantially along the lengththereof, and having a convex arcuate tracking surface (52, 252) with acentre axis ("A", "I") substantially coaxial with said centre axis ofsaid inner and outer edges of said conveyor.
 13. The curved conveyorsection of claim 1, wherein said continuous loop drive means drivablyengages said driven receptors at said article carrying portion of saidcurved conveyor belt.
 14. The curved conveyor section of claim 13,wherein said continuous loop drive means is substantially co-planar withthe article carrying portion of said curved conveyor belt.
 15. Thecurved conveyor section of claim 12, wherein said convex arcuatetracking surface on said guide rail is of substantially constant radiusabout its centre axis.
 16. The curved conveyor section of claim 14,wherein of each said elongate roller members is cylindrical along itslength.